As many as one in three dogs exhibit behavior like tail chasing, obsessive licking, compulsive barking — even chasing lights reflected on walls. So, what makes them act this way?

We don’t know exactly why they do it, but researchers have identified four factors that may increase a dog’s risk of developing abnormal repetitive behavior. One is belonging to a newbie pooch parent, what with their fledgling training skills and knowledge of canine behavior. Another is living in a large family, likely due to the commotion and relatively less attention. But being the only dog is another risk factor. Dogs that get little exercise are also at risk. As in people, exercise is a canine stress-reliever.

In fact, providing mental stimulation and exercise is important for all dogs. Working with a trainer is also key to solving behavioral issues.